Robust Integrated Circuit Package

ABSTRACT

The base of an integrated circuit package comprises a first side, and a second side opposing the first side. The base further comprises, a base mounting section, a die mounting section, and a recessed section. The recessed section comprises a recess between the die mounting section and the base mounting section. The base further comprises an opening extending through the base from the first side to the second side. At least a portion of the recess intersects with the opening.

BACKGROUND

An integrated circuit (IC) is a circuit in which electronic componentsof the circuit are fabricated as a single unit, e.g., on a substrate ofsemiconductor material. An IC package is a structure supporting an ICthat serves one or more important functions. Often, an IC package servesto protect an IC from environmental factors (e.g., that might causephysical damage or corrosion), regulates thermal properties of the IC(e.g., to prevent thermal fatigue), arranges for electrical connectivityof the IC to other electronics, and/or increases the mechanicalstability of the IC on a given substrate to which the IC is mounted. Itis challenging to design an IC package that robustly serves one or moreof these purposes, particularly when the IC is to be used in certaindemanding environments.

SUMMARY

Embodiments of the present disclosure are generally directed to ICpackages. Particular embodiments are able to provide robust protectionagainst external stressors. Such stressors may include, but are notlimited to, thermal fatigue during operation of the IC, and mechanicalstress applied during installation of the IC package and/or resultingfrom thermal expansion/contraction of IC components.

In particular, one or more embodiments include an IC package comprisinga base and an electrically-insulating die housing. The base comprises afirst side, a second side opposing the first side, a base mountingsection and a die mounting section. The base further comprises arecessed section. The recessed section comprises a recess between thedie mounting section and the base mounting section. The base furthercomprises an opening extending through the base from the first side tothe second side. At least a portion of the recess intersects with theopening. The electrically-insulating die housing is mounted to the diemounting section.

One or more other embodiments include an IC package comprising a base.The base comprises a die mounting section, a base mounting section, anda recessed section positioned between the die mounting section and thebase mounting section. The IC package further comprises an opening thatextends through the base at the base mounting section and the recessedsection. The recessed section is configured to reduce mechanical stresson the die mounting section when torque is applied to a fastener that isdisposed within the opening.

One or more other embodiments include an IC package comprising a base.The base comprises a die mounting section, a base mounting section, anda recessed section positioned between the die mounting section and thebase mounting section. The IC package further comprises anelectrically-insulating die housing mounted to the die mounting section.The die housing comprises a die cavity and a lead channel spaced apartfrom the die cavity. The IC package further comprises a lead seatedpartially within the lead channel and extending away from the diecavity. The lead avoids cracking of the die housing due to mechanicalstress imposed by the lead upon the die housing when the lead issoldered to a pad on a mounting surface and one thousand ambienttemperature cycles between −40 degrees Celsius and 85 degrees Celsiusare performed.

One or more other embodiments include a method of mounting an ICpackage. The method comprises inserting a fastener through an openingextending through the integrated circuit package. The opening is at arecessed section and a base mounting section of the integrated circuitpackage. The method further comprises mating a head of the insertedfastener to a mating surface of the base mounting section such that thehead of the fastener is spaced apart from the recessed section. Themethod further comprises applying torque to the inserted fastener tosecure the base mounting section between the mated head of the fastenerand a mounting surface while keeping the head of the fastener spacedapart from the recessed section.

According to particular embodiments, any of the embodiments above mayfurther include one or more of the features discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are illustrated by way of example andare not limited by the accompanying figures with like referencesindicating like elements. In general, the use of a reference numeralshould be regarded as referring to the depicted subject matter accordingto one or more embodiments, whereas discussion of a specific instance ofan illustrated element will append a letter designation thereto (e.g.,discussion of a lead 70, generally, as opposed to discussion ofparticular instances of particular leads 70 a, 70 b).

FIGS. 1A and 1B are schematic diagrams of an example IC package asviewed from the top and side, respectively, according to one or moreembodiments of the present disclosure.

FIG. 2 is a schematic diagram of another example IC package as viewedfrom the top, according to one or more embodiments of the presentdisclosure.

FIG. 3 is a schematic diagram of yet another example IC package mountedto a mounting surface and as viewed from the side, according to one ormore embodiments of the present disclosure.

FIG. 4 is a schematic diagram of a further example IC package mounted toa mounting surface and as viewed from the side, according to one or moreembodiments of the present disclosure.

FIGS. 5 and 6 are isometric schematic diagrams of an example six-lead ICpackages, each according to one or more embodiments of the presentdisclosure.

FIG. 7 is a flow diagram of an example method, according to one or moreembodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the embodiments andillustrate the best mode of practicing the embodiments. Upon reading thefollowing description in light of the accompanying drawing figures,those skilled in the art will understand the concepts of the disclosureand will recognize applications of these concepts not particularlyaddressed herein. It should be understood that these concepts andapplications fall within the scope of the disclosure and theaccompanying claims.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element such as a layer, region, orsubstrate is referred to as being “on” or extending “onto” anotherelement, it can be directly on or extend directly onto the other elementor intervening elements may also be present. In contrast, when anelement is referred to as being “directly on” or extending “directlyonto” another element, there are no intervening elements present.Likewise, it will be understood that when an element such as a layer,region, or substrate is referred to as being “over” or extending “over”another element, it can be directly over or extend directly over theother element or intervening elements may also be present. In contrast,when an element is referred to as being “directly over” or extending“directly over” another element, there are no intervening elementspresent. It will also be understood that when an element is referred toas being “connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

Relative terms such as “below” or “above” or “upper” or “lower” or“horizontal” or “vertical” may be used herein to describe a relationshipof one element, layer, or region to another element, layer, or region asillustrated in the Figures. It will be understood that these terms andthose discussed above are intended to encompass different orientationsof the device in addition to the orientation depicted in the Figures.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including” when used herein specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

As discussed above, an IC package is a structure for supporting an ICthat may, for example, protect an IC from environmental factors (e.g.,that might cause physical damage or corrosion), regulate thermalproperties of the IC (e.g., to prevent thermal fatigue), arrange forelectrical connectivity of the IC to other electronics, and/or increasethe mechanical stability of the IC on a given substrate to which the ICis mounted. FIG. 1A is a schematic view of an IC package 100 that may beuseful for one or more such purposes and/or other useful purposes, inaccordance with one or more embodiments of the present disclosure.

The IC package 100 comprises a base 10. In FIG. 1A, a first side 11 ofthe base 10 is visible. The base may be made, in whole or in part, ofone or more materials (e.g., alloys, composites, ceramics) having a highthermal conductivity (e.g., Copper-Tungsten (CuW),Copper-Molybdenum-Copper (CMC)). In some particular example embodiments,the base is made from CuW 15:85, CuW 10:90, CMC 1:1:1, or CMC 1:3:1.

The base 10 comprises a base mounting section 20, a die mounting section30, and a recessed section 40 positioned between the base mountingsection 20 and the die mounting section 30. The base 10 furthercomprises an opening 21 at the base mounting section 20 and the recessedsection 40.

FIG. 1B illustrates a side view of the same example IC package 100 shownin FIG. 1A. As shown in FIG. 1B, the base 10 of the IC package 100comprises a first side 11 (e.g., a “top” side), a second side 12 (e.g.,a “bottom” side), and a lateral side 13. The second side 12 opposes thefirst side 11. The lateral side 13 connects the first and second sides11, 12.

As can be seen in FIG. 1B, the recessed section 40 of the IC package 100comprises a recess 41 that is between the die mounting section 30 andthe base mounting section 20. Accordingly, a thickness of the base 10throughout the recessed section 40, as measured between the first andsecond sides 11, 12, is less than the thickness of the base 10throughout the base mounting section 20. For example, the thickness ofthe recessed section 40 may be between 10 and 20 mils less than thethickness of the base mounting section 20. In other examples, thedifference in thickness may be even greater. In this example, thethickness of the base 10 throughout the recessed section 40 is also lessthan the thickness of the base 10 throughout the die mounting section30.

Although FIG. 1B depicts the thickness of the base throughout the basemounting section 20 as having the same thickness as the base 10throughout the die mounting section 30, other embodiments of the ICpackage 100 may include a base mounting section 20 and die mountingsection 30 of different thicknesses.

The base 10 further comprises an opening 21 extending through the base10 from the first side 11 to the second side 12. Although the opening 21does not extend through the lateral side 13 in this example, otherexamples of the IC package 100 may include an opening 21 that doesextend through the lateral side 13, as will be discussed in furtherdetail below.

As shown in FIG. 1B, at least a portion of the recess 41 intersects withthe opening 21. In this particular example, the opening 21 extendsthrough the base 10 at both the base mounting section 20 and therecessed section 40. The opening 21 may be used to mount the IC package100 to a mounting surface (e.g., a printed circuit board) by use of afastener 60 (e.g., a bolt, a screw), as shown in FIG. 2. In someembodiments, a thermal interface material (e.g., thermal grease,adhesive, or tape) (not shown) may be used between the base 10 and themounting surface to enhance thermal performance.

FIG. 2 illustrates a variation of the example IC package 100 accordingto particular embodiments, such that the first side 11 of the IC package100 is in view. In particular, FIG. 2 includes all of the elements ofthe IC package 100 discussed above with respect to FIGS. 1A and 1B, aswell as a fastener 60 for mounting the IC package 100 to a mountingsurface, and other components supporting electrical connectivity betweenan IC die and other electronics as may be on the mounting surface, aswill be further discussed below.

To mount the IC package 100 to a mounting surface, the fastener 60 isinserted through the opening 21 at the base mounting section 20 andrecessed section 40. In addition, a head 61 of the inserted fastener 60is mated to a mating surface 22 of the base mounting section 20. Torqueis applied to the inserted fastener 60 (e.g., using a tool inserted intoa socket 62 in the head 61 of the fastener 60) to secure the basemounting section 20 between the mated head 61 of the fastener 60 and themounting surface (which will be shown in further examples below).

In the example of FIG. 2, the IC package 100 further comprises anelectrically-insulating die housing 50 mounted to the die mountingsection 30. The die housing 50 comprises a die cavity 51. The die cavity51 may, for example, accept insertion of an IC die, as will be shown anddiscussed in greater detail below.

The IC package 100 further comprises a lead 70 extending away from thedie cavity 51. The lead is connected to a lead pad 72 and is seatedpartially within a lead channel 52 of the die housing 50, as shown inFIG. 3. Note that although the example IC package 100 of FIG. 2illustrates a single lead 70, other embodiments of the IC package 100will be discussed below that comprise one or more additional leads 70.For example, embodiments that include two leads may use one lead tocarry positive supply voltage, and the other to carry negative supplyvoltage or ground. Embodiments that use three leads may respectively useone lead for positive supply voltage, negative supply voltage, andground. Embodiments that use four leads may, for example, use two leadsfor positive and negative supply voltage, respectively, and two leadsfor input and output signaling, respectively. Other embodiments may useone or more leads to carry power, signaling, reference voltage, and/orground, among other things.

FIG. 3 illustrates the IC package 100 of FIG. 2 as viewed from the side,mounted to a mounting surface 80, and comprising an IC die 90 that iselectrically connected to a pad 81 on the mounting surface 80 via thelead 70. From the illustration of FIG. 3, it can be seen that the head61 of the inserted fastener 60 is mated to the mating surface 22 of thebase mounting section 20 such that the head 61 of the fastener 60 isspaced over and apart from the recessed section 40 of the base 10.

According to embodiments, torque is applied to the inserted fastener 60to secure the base mounting section 20 between the mated head 61 of thefastener 60 and the mounting surface 80 while keeping the head 61 of thefastener 60 spaced apart from the recessed section 40. Although typicalembodiments of the present disclosure may include applying between 40and 60 inch-ounces of torque to the fastener 60 in order to mount the ICpackage 100 to the mounting surface 80, other embodiments may apply evenmore torque (e.g., up to 80 inch-ounces). In some embodiments, thistorque may impose mechanical stress on the die mounting section 30 viathe recessed section 40 and base mounting section 20. Accordingly, in atleast some embodiments, the recessed section 40 is configured to reducethe mechanical stress applied to the die mounting section 30 when torqueis applied to the fastener 60 disposed within the opening 21. In somesuch embodiments, the recessed section 40 is configured to reducemechanical stress on the die mounting section 30 particularly whentorque is applied to the fastener 60 while the mating surface 22 andhead 61 of the fastener 60 are mated.

FIG. 3 also shows lead 70 of the IC package 100 connected to a pad 81 onthe mounting surface 80 by solder 82. The lead 70 extends away from thedie cavity 51 and is seated partially within a lead channel 52 of thedie housing 50. In some embodiments, the lead 70 is configured to avoidcracking of the die housing 50 due to mechanical stress imposed by thelead 70 upon the die housing 50 when the lead 70 is soldered to the pad81 on the mounting surface 80 and, e.g., one thousand ambienttemperature cycles between −40 degrees Celsius and 85 degrees Celsiusare performed. In some embodiments, the lead 70 comprises a side 71having a thickness of not more than four mils, e.g., to avoid suchcracking.

The IC package 100 illustrated in FIG. 3 further comprises an IC die 90seated partially within the die cavity 51. The IC die 90 is connected tothe lead pad 72 of the lead 70 by a bond wire 91. According to one ormore other embodiments, the IC die 90 may be seated entirely within thedie cavity 51.

The die housing 50 is may be made of plastic, resin, polymer, and/orceramic material, which electrically insulates the IC die 90 fromundesired static or other unintended electrical sources. As shown inFIG. 4, the IC package 100 may further comprise a cap 92 mounted to thedie housing 50. In some embodiments, the cap 92 comprises athermally-conductive material or shape, such that the cap acts as a heatspreader and/or heat sink. The cap 92 may additionally or alternativelybe made of plastic, resin, polymer, and/or ceramic material, whichelectrically insulates the IC die 90 from undesired static or otherunintended electrical sources. In some embodiments, the cap 92 and diehousing 50 are made of the same material(s).

FIG. 5 illustrates an isometric view of another example IC package 100.The IC package 100 of FIG. 5 comprises a base 10 and anelectrically-insulating die housing 50. The die housing 50 is mounted toa die mounting section 30 of the base 10, as discussed in examplesabove. This particular example of the IC package 100 comprises two basemounting sections 20 a, 20 b, each separated from the base 10 by arespective recessed section 40 a, 40 b. Each recessed section 40 a, 40 bcomprises a respective recess 41 a, 41 b between a corresponding basemounting section 20 a, 20 b and the die mounting section 30. The base 10further comprises two openings 21 a, 21 b. Each opening 21 a, 21 b,extends through the base 10 from a first side 11 of the base 10 to asecond side 12 of the base 10. Each opening 21 a, 21 b, also extendsthrough respective lateral sides 13 a, 13 b of the base 10. Each opening21 a, 21 b intersects with a respective recess 41 a, 41 b of therecessed sections 40 a, 40 b, respectively. As shown in FIG. 5, each ofthe base mounting sections 20 a, 20 b comprises a respective matingsurface 22 a, 22 b for mating with one or more fasteners (not shown inFIG. 5).

The die housing 50 illustrated in FIG. 5 comprises a die cavity 51 andsix lead channels 52 a-f. The IC package 100 in this example furthercomprises six leads 70 a-f, each having a respective lead pad 70 a-f.Each of the leads 70 a-f is spaced apart from the die cavity 51 and ispartially seated in a respective lead channel 52 a-f. Lead pads 72 a-fof the leads 70 a-f are also each seated, at least partially, in therespective lead channels 52 a-f.

Other embodiments of the IC package 100 may comprise additional, fewer,or different base mounting sections 20. For example, the IC package 100may comprise three base mounting sections 20, each extending away fromthe die mounting section 30 in different directions (e.g., two inopposing directions and one laterally). Other embodiments mayadditionally or alternatively include a plurality of base mountingsections 20 that extend away from the die mounting section 30 in thesame direction. Further, some embodiments may include one or more basemounting sections 20 that are connected to the die mounting section 30without an intervening recessed section 40.

Embodiments of the present disclosure may additionally or alternativelycomprise one or more leads 70 that extend in any direction away from thedie cavity 51. Although the leads 70 of embodiments discussed above areall depicted as straight, other embodiments may include one or moregull-wing leads, J-leads, butt-leads, S-leads, spider J-leads, clipJ-leads, and/or through-hole pins, for example. Accordingly, particularembodiments may correspondingly be suitable for a variety of surfacemounting or through-hole mounting applications, for example.

Further, the IC package 100 may comprise a cap 92 mounted to the diehousing 50 as discussed above. Another example of an IC package 100comprising such a cap 92 is shown in FIG. 6.

As shown in FIG. 7, other embodiments of the present disclosure includea method 200 of mounting an IC package 100. The method 200 comprisesinserting a fastener 60 through an opening 21 extending through the ICpackage 100 (block 210). The opening 21 is at a recessed section 40 anda base mounting section 20 of the IC package 100. The method 200 furthercomprises mating a head 61 of the inserted fastener 60 to a matingsurface 22 of the base mounting section 20 such that the head 61 of thefastener 60 is spaced apart from the recessed section 40 (block 220).The method 200 further comprises applying torque to the insertedfastener 60 to secure the base mounting section 20 between the matedhead 61 of the fastener 60 and a mounting surface 80 while keeping thehead 61 of the fastener 60 spaced apart from the recessed section 40(block 230).

Embodiments of the present disclosure may additionally or alternativelyinclude any compatible combination of features described above or in theclaims below. Embodiments may, of course, be carried out in other waysthan those specifically set forth herein without departing fromessential characteristics of the invention. The present embodiments areto be considered in all respects as illustrative and not restrictive,and all changes coming within the meaning and equivalency range of theappended claims are intended to be embraced therein.

What is claimed is:
 1. An integrated circuit package comprising: a basecomprising: a first side, and a second side opposing the first side; abase mounting section and a die mounting section; a recessed sectioncomprising a recess between the die mounting section and the basemounting section; an opening extending through the base from the firstside to the second side, wherein at least a portion of the recessintersects with the opening; an electrically-insulating die housingmounted to the die mounting section.
 2. The integrated circuit packageof claim 1, wherein the base has a thickness measured between the firstand second sides, the thickness of the base throughout the recessedsection being less than the thickness of the base throughout the basemounting section.
 3. The integrated circuit package of claim 2, whereinthe thickness of the base throughout the recessed section is also lessthan the thickness of the base throughout the die mounting section. 4.The integrated circuit package of claim 1, wherein the base furthercomprises a lateral side connecting the first and second sides, and theopening further extends through the lateral side.
 5. The integratedcircuit package of claim 1, wherein the base mounting section comprisesa mating surface configured to mate with a head of a fastener that isspaced over the recessed section when the fastener is disposed withinthe opening.
 6. The integrated circuit package of claim 5, wherein therecessed section is configured to reduce mechanical stress on the diemounting section when torque is applied to the fastener while the matingsurface and head of the fastener are mated.
 7. The integrated circuitpackage of claim 1, wherein: the die housing comprises a die cavity anda lead channel spaced apart from the die cavity; the integrated circuitpackage further comprises a lead seated partially within the leadchannel and extending away from the die cavity, the lead comprising aside having a thickness of not more than four mils.
 8. The integratedcircuit package of claim 7, wherein the lead avoids cracking of the diehousing due to mechanical stress imposed by the lead upon the diehousing when the lead is soldered to a pad on a mounting surface and onethousand ambient temperature cycles between −40 degrees Celsius and 85degrees Celsius are performed.
 9. The integrated circuit package ofclaim 1, further comprising an integrated circuit die, wherein the diehousing comprises a die cavity and the integrated circuit die is seatedat least partially within the die cavity.
 10. An integrated circuitpackage comprising: a base comprising a die mounting section, a basemounting section, and a recessed section positioned between the diemounting section and the base mounting section; an opening that extendsthrough the base at the base mounting section and the recessed section;wherein the recessed section is configured to reduce mechanical stresson the die mounting section when torque is applied to a fastener that isdisposed within the opening.
 11. The integrated circuit package of claim10, wherein: the base further comprises a first side and a second sideopposing the first side; the base has a thickness measured between thefirst and second sides; the thickness of the base throughout therecessed section is less than the thickness of the base throughout thebase mounting section.
 12. The integrated circuit package of claim 11,wherein the thickness of the base throughout the recessed section isalso less than the thickness of the base throughout the die mountingsection.
 13. The integrated circuit package of claim 10, wherein: thebase further comprises a first side, a second side opposing the firstside, and a lateral side connecting the first and second sides; toextend through the base at the base mounting section and the recessedsection, the opening extends through the base from the first side to thesecond side and through the lateral side.
 14. The integrated circuitpackage of claim 10, wherein: the base mounting section comprises amating surface configured to mate with a head of the fastener that isspaced over the recessed section when the fastener is disposed withinthe opening; to reduce the mechanical stress applied to the die mountingsection when the torque is applied to the fastener, the recessed sectionis configured to reduce the mechanical stress when the torque is appliedto the fastener while the mating surface and the head of the fastenerare mated.
 15. The integrated circuit package of claim 10, furthercomprising: an electrically-insulating die housing mounted to the diemounting section, the die housing comprising a die cavity and a leadchannel spaced apart from the die cavity; a lead seated partially withinthe lead channel and extending away from the die cavity, the leadcomprising a side having a thickness of not more than four mils.
 16. Theintegrated circuit package of claim 15, wherein the lead avoids crackingof the die housing due to mechanical stress imposed by the lead upon thedie housing when the lead is soldered to a pad on a mounting surface andone thousand ambient temperature cycles between −40 degrees Celsius and85 degrees Celsius are performed.
 17. The integrated circuit package ofclaim 15, further comprising an integrated circuit die seated at leastpartially within the die cavity.
 18. An integrated circuit packagecomprising: a base comprising a die mounting section, a base mountingsection, and a recessed section positioned between the die mountingsection and the base mounting section; an electrically-insulating diehousing mounted to the die mounting section, the die housing comprisinga die cavity and a lead channel spaced apart from the die cavity; a leadseated partially within the lead channel and extending away from the diecavity, wherein the lead avoids cracking of the die housing due tomechanical stress imposed by the lead upon the die housing when the leadis soldered to a pad on a mounting surface and one thousand ambienttemperature cycles between −40 degrees Celsius and 85 degrees Celsiusare performed.
 19. The integrated circuit package of claim 18, whereinthe lead comprises a side having a thickness of not more than four mils.20. A method of mounting an integrated circuit package, the methodcomprising: inserting a fastener through an opening extending throughthe integrated circuit package, wherein the opening is at a recessedsection and a base mounting section of the integrated circuit package;mating a head of the inserted fastener to a mating surface of the basemounting section such that the head of the fastener is spaced apart fromthe recessed section; applying torque to the inserted fastener to securethe base mounting section between the mated head of the fastener and amounting surface while keeping the head of the fastener spaced apartfrom the recessed section.